U.S. patent number 3,760,550 [Application Number 05/219,254] was granted by the patent office on 1973-09-25 for collapsible truss structure.
This patent grant is currently assigned to Armco Steel Corporation. Invention is credited to Warren E. Mueller, David C. Yocom.
United States Patent |
3,760,550 |
Mueller , et al. |
September 25, 1973 |
COLLAPSIBLE TRUSS STRUCTURE
Abstract
A metal truss structure is disclosed which is prefabricated and
capable of being shipped in a collapsed condition in which it
occupies a space on the order of four inches by four inches by
twenty-eight feet, and which can be erected easily at the site into
a roof truss capable of spanning all widths common in residential
structures and some commercial structures, while maintaining a
desired and predetermined roof pitch, as for example 4:12. A half
truss suitable for panelized construction or for modular
construction, and having many of the features of the basic truss
structure, is also disclosed.
Inventors: |
Mueller; Warren E. (Middletown,
OH), Yocom; David C. (Middletown, OH) |
Assignee: |
Armco Steel Corporation
(Middletown, OH)
|
Family
ID: |
22818527 |
Appl.
No.: |
05/219,254 |
Filed: |
January 20, 1972 |
Current U.S.
Class: |
52/641 |
Current CPC
Class: |
E04C
3/005 (20130101); E04B 1/34326 (20130101) |
Current International
Class: |
E04C
3/00 (20060101); E04B 1/343 (20060101); E04b
007/16 () |
Field of
Search: |
;52/641,645,640,646,67,118,648,109,108,639 ;182/149,153,155
;287/51.4,3 ;248/277,439 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
483,168 |
|
1938 |
|
GB |
|
839,854 |
|
1952 |
|
DT |
|
Primary Examiner: Abbott; Frank L.
Assistant Examiner: Friedman; Carl D.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A roof truss comprising an upper chord and a lower chord, each
constituted by channel members having lipped flanges, and a pair of
web members extending therebetween, said web members at their lower
ends being pivotably connected together and to an element slidable
along said lower chord, one of said web members, at its upper end,
being pivotably connected to said upper chord adjacent the inner
end thereof, and the other of said web members, at its upper end,
being pivotably connected to an element slidable along said upper
chord, said slidable elements being plain channel pieces slidable
within said lipped channel members, whereby said truss, in
collapsed condition, presents a long, thin and narrow package, and
is capable of being erected, with said slidable elements adjusting
themselves along the respective chords, said slidable elements then
being secured in fixed position.
2. A truss according to claim 1, wherein said upper and lower
chords are provided with extensions telescopingly arranged with
respect to said chords, and said extensions, at their outer ends
are pivotably connected together.
3. A truss according to claim 2, wherein said chords are
constituted by channel members having lipped flanges, and said
extensions are plain channel pieces slidable within said lipped
channel members.
4. A roof truss comprising a one-piece lower chord and an upper
chord composed of two portions secured together at the middle of
the truss, a pair of web members on each side of the middle, each
pair of web members at their lower ends being pivotably secured
together and to an element slidable along said lower chord, one of
the web members of each pair, at its upper end, being pivotably
connected to the respective upper chord portion adjacent the middle
of the truss, and the other web member of each pair, at its upper
end, being pivotably connected to an element slidable along the
respective upper chord portion, whereby said truss, in collapsed
condition, presents a long, thin and narrow package, and is capable
of erection by raising the middle of the upper chord, with said
slidable elements adjusting themselves along the respective chords,
said slidable elements then being secured in fixed position.
5. A truss according to claim 4, wherein said upper chord portions
at their adjacent ends, are mitered to provide a desired,
predetermined roof pitch, and are held together by a strap of thin
bendable material.
6. A truss according to claim 5, wherein a connector element is
provided to secure said upper chord portions in the position
providing said desired roof pitch.
7. A truss according to claim 4, wherein the inner ends of said
upper chord portions are spaced apart, and connected together by a
channel shaped insert engaging in and secured to, the proximate
ends of said chord portions, said insert having its web slotted,
and having its lower flange and the lower portion of the web
relieved, whereby during erection of the truss, the portions of the
insert web separated by said slot overlap each other, a hole in
said web on each side of said slot, said holes being located such
that they will coincide when the desired roof pitch is attained,
and may be fixed in position by fastening means passing through
said aligned holes.
8. A truss according to claim 4, wherein said chords are
constituted by channel members having lipped flanges, and said
slidable elements are plain channel pieces slidable within said
lipped channel members.
9. A truss according to claim 4, wherein said upper and lower
chords are provided with extensions telescopingly arranged with
respect to said chords.
10. A truss according to claim 9, wherein said extensions are
provided at the outer ends of the upper and lower chords, and said
extensions, at their outer ends, are pivotably connected
together.
11. A truss according to claim 9, wherein said chords are
constituted by channel members having lipped flanges, and said
extensions are plain channel pieces slidable within said lipped
channel members.
12. A half roof truss comprising an upper chord and a lower chord,
each constituted by channel members having lipped flanges, and a
pair of web members extending therebetween, said web members at
their lower ends being pivotably connected together and to an
element slidable along said lower chord, one of said web members,
at its upper end, being pivotably connected to said upper chord
adjacent the inner end thereof, and the other of said web members,
at its upper end, being pivotably connected to an element slidable
along said upper chord, said slidable elements being plain channel
pieces slidable within said lipped channel members, and stop means
for said first named slidable element at the inner end of said
lower chord, whereby said half truss, in collapsed condition,
presents a long, thin and narrow package, and is capable of being
erected, with said slidable elements adjusting themselves along
their respective chords, said slidable elements being then secured
in fixed position.
13. A roof truss according to claim 4, wherein said upper chord is
a one-piece member, said chords being constituted by lipped channel
members, said upper chord having its web, its lower flange and lip,
and its upper lip relieved, and its upper flange having a line of
weakness transversely of the length of said chord, whereby said
upper chord may be bent along said line of weakness to provide a
ridge, and a connector element to secure the relieved parts
together in an angular relation.
14. A truss according to claim 12, wherein said upper and lower
chords are provided with extensions telescopingly arranged with
respect to said chords, and said extensions, at their outer ends
are pivotably connected together.
15. A truss according to claim 14, wherein said chords are
constituted by channel members having lipped flanges, and said
extensions are plain channel pieces slidable within said lipped
channel members.
16. A truss according to claim 12, wherein each of said chords is
composed of a major piece and a minor extension piece in
telescoping relation, the combined length of each major piece and
minor extension, when extended, constituting the length of said
upper and lower chords respectively, the upper chord having its
extension piece at its inner end, and the lower chord having its
extension piece at its outer end, the outer end of the major piece
of said upper chord being pivotably secured to the outer end of the
extension piece of the said lower chord, a pair of web members
extending between said chords, said web members, at their lower
ends, being pivotably connected together and to an element slidable
along the major piece of said lower chord, one of said web members,
at its upper end, being pivotably connected to the end of the
extension piece of the said upper chord, and the other of said web
members at its upper end being pivotably connected to an element
slidable along the major piece of said upper chord, and stop means
at the inner end of the major piece of said lower chord, whereby
said truss in fully collapsed condition presents a long, thin and
narrow package and is capable of being erected with said first
named slidable element resting against said stop means, and said
extension pieces fully extended, said second named slidable element
adjusting itself along said upper chord, and said truss also being
capable of being partially collapsed, there being an intermediate
stop member in the major portion of said lower chord whereby said
truss may be partially collapsed and the telescoping extensions
withdrawn to present a relatively low and relatively narrow package
for shipment.
17. A truss according to claim 16, wherein the major pieces of said
chords are constituted by channel members having lipped flanges,
and said slidable elements and extension pieces are plain channel
pieces slidable within said lipped channel members.
Description
BACKGROUND OF THE INVENTION
The building of roof trusses on the building site in residential
and in small commercial buildings is an expensive and time
consuming operation. In addition, where a large number of such
trusses need be built, they rarely turn out to be perfectly
uniform. As a result, the building industry has gone to the
prefabricated roof truss which eliminates the costly on-site labor
time. When these prefabricated wooden trusses are completely
assembled, a special truck is required for shipping them to the job
site and one such truck can usually just about carry the number of
trusses required for a single home. Because of the shape of the
assembled trusses and the configuration of the special truck which
must be used, it is impossible to carry any additional construction
materials. Furthermore, such prefabricated trusses must be ordered
to size for each individual structure. With trusses of longer spans
the weight of the assembled wood trusses becomes excessive since it
is necessary to use heavier wood members. In fact, the relatively
few sizes of standard lumber available often results in a structure
which is over-adequate for the intended purpose.
A complete truss according to the present invention occupies an
area of about four inches by four inches by twenty-eight feet when
fully collapsed, so that many such trusses can be stacked easily on
an ordinary flatbed truck or trailer which may also be used for the
delivery of bulk materials. Since the truss of this invention is
capable of use for any commonly used span, such trusses may be
ordered in large quantities and stockpiled for future use and need
not be specially ordered and built for each particular
building.
The use of trusses according to the present invention makes it
possible to optimize the steel members which make up the truss for
the load requirements involved and thus one is not limited to
standard available sizes. This factor combined with the increased
modulus and strength of steel over wood results in a noticeably
lighter truss which is therefore easier to handle during
erection.
Beyond the provision of collapsible trusses per se, the invention
also contemplates a panelized construction and a modular
construction. In a panelized construction a plurality of half
trusses according to the invention are assembled with a roof
decking or sheathing so that at the site the several trusses may be
erected to provide a complete roof. In a modular construction, the
half trusses are assembled with roof decking, a side wall, and half
end walls; and plumbing, duct work, and electrical wiring are all
installed at the factory. Thus, two such modular half buildings may
be assembled at the site into a complete building.
BRIEF SUMMARY
According to the invention, a full truss comprises a bottom chord
member, a top chord member, and two web members on each side of the
middle. The chord members are steel channel members and have
telescoping extensions at their outer ends. The telescoping
extensions are pivotally connected. In a full truss, the upper
chord member is provided in two pieces of half length which may be
mitered at their adjacent ends to provide a desired pitch, say 4:12
for the roof; and they are held together by a strap of relatively
thin bendable material. Extensions are provided for the chord
members so the truss may be used for a variety of spans, while
still maintaining the predetermined pitch. On each side of middle
there are provided two web members in a V configuration. One arm of
each V is pivotably secured at its upper end adjacent the inner end
of the respective upper chord piece. The upper end of the other arm
of the V is pivotably secured to an element which is slidable along
the respective upper chord piece. The lower ends of the V's on each
side are pivotably secured to each other, and to members slidable
along the lower chord on each side of center. While the structure
above outlined provides a symmetrical truss, it will be understood
that for some structures it may be desirable to provide upper chord
pieces of unequal length.
Thus, the complete truss may constitute in its collapsed condition
a package having dimensions of about four inches by four inches by
twenty-eight feet. By lifting up the adjacent inner ends of the top
chord pieces, thereby bending the connecting strap, the web members
adjust themselves by sliding along the upper and lower chords until
the predetermined pitch is attained, and the extensions in the
upper chord members also adjust themselves. In this manner, a truss
of minimum span is produced. If a longer span is required, the
extension members in the lower chord member are first extended
equally from each end until the desired span is reached, and then
fixed at these locations by suitable means, such as self-threading
screws. Erecting into final condition continues as previously
described, resulting in a truss having an increased span, but with
the same predetermined and desired pitch. When the truss is thus
fully erected, the several remaining slidable parts are also fixed
in position by suitable means, as for example, self-threading
screws.
The half truss, whether for use for the panelized construction or a
modular construction as above outlined, is basically one half of a
complete truss; and the half trusses for the two types of
construction are basically similar, with minor variations.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is a plan view of a full truss in fully collapsed
condition.
FIG. 1A is an elevational view showing the truss in partially
erected condition.
FIG. 1B is a view similar to FIG. 1A showing the truss in a
further,but still partially erected condition.
FIG. 1C is an elevational view showing the truss in fully erected
condition.
FIG. 2 is a cross sectional view on an enlarged scale, taken on the
line 2--2 of FIG. 1C.
FIG. 3 is a fragmentary perspective view of the joint between the
upper and lower chord extensions.
FIG. 4 is a fragmentary cross sectional view taken on the line 4--4
of FIG. 1C.
FIG. 5 is a perspective view of the structure shown in FIG. 4.
FIG. 6 is a perspective view of an insert which may be used at the
joint between the two upper chords.
FIG. 7A is a fragmentary perspective view of the two upper chords
with the insert of FIG. 6 in place, the truss being in its
collapsed condition.
FIG. 7B is a view similar to FIG. 7A showing the condition when the
truss is erected.
FIG. 8A is an elevational view of the two upper chords showing a
modification, the chords being in collapsed condition.
FIG. 8B is a view similar to FIG. 8A showing the condition when the
truss is erected.
FIG. 9 is a plan view of a half truss suitable for panelized
construction, in collapsed condition.
FIG. 10 is an elevational view of the half truss in erected
condition.
FIG. 11 is a fragmentary end elevational view of the connection
between the upper and lower chords, as seen from the left of FIG.
10.
FIG. 12 is a plan view of a modified half truss, suitable for
modular construction, in collapsed condition.
FIG. 13 is an elevational view of the half truss of FIG. 12 in
partially erected condition.
FIG. 14 is an elevational view of the same half truss in fully
erected condition.
FIG. 15 is a cross sectional view, on an enlarged scale, taken on
the line 15--15 of FIG. 14.
FIG. 16 is a cross sectional view taken on the line 16--16 of FIG.
14.
FIG. 17 is a view similar to FIG. 8A, showing a modification.
FIG. 18 is a view similar to FIG. 8B, showing the same
modification.
DETAILED DESCRIPTION
Referring first to FIGS. 1 to 8B which disclose a full truss
according to the invention, the collapsed truss package is shown at
10 in FIG. 1. For most purposes, this package will be four inches
by four inches by twenty-eight feet. It is assumed that the truss
is designed for a conventional roof pitch of 4:12, but it should be
noted that any pitch desired in the intended construction is
possible. The progressive erection of truss from the condition of
FIG. 1 to the condition of FIG. 1C is shown in FIGS. 1A, 1B and
1C.
Basically, the truss consists of a bottom chord indicated generally
at 13 and an upper chord consisting of two pieces 14 and 14a. These
chord pieces are all in the form of channel members having lipped
or return flanges and the pieces 14 and 14a may be joined together
at their adjacent ends by a strap member 15 of relatively thin
bendable material.
In the embodiment shown, the bottom chord 13 is provided with the
telescoping extensions 16 and 16a and the upper chord pieces 14 and
14a are provided with the telescoping extensions 17 and 17a,
respectively. The extension members 16, 16a, 17, and 17a are in the
form of plain channels without the lipped flanges. These members
are disposed back-to-back and are dimpled at the center as
indicated at 17b and 16b in FIG. 2 and they are secured together by
means of a bolt 25 passing through the aligned openings 18. It will
be understood that these members can also be fastened with rivets,
or self-drilling screws. This is true for any bolted connection
described herein.
On each side of the middle there are a pair of webs in a V
configuration. Thus, there are the relatively short web members 19
and 20 and the relatively long web members 21 and 22. The upper
ends of the web members 21 and 22 are pivotably secured to the
respective upper chord pieces 14 and 14a. This connection is
pivotable but not slidable. The upper ends of the web members 19
and 20 are pivotably connected to sliding channel elements 23 by
means of bolts 24 as best seen in FIGS. 4 and 5, where a typical
construction connecting the upper end of the web 19 is shown. The
end of the web member 19 is dimpled as at 19a and the bolt 24 is
passed through the openings in the member 23 and in the center of
the dimple 19a. It will be understood that the construction shown
in FIGS. 4 and 5 is found at the upper end of each of the webs 19
and 20.
The lower ends of the webs 19 and 20 are pivotably secured to a
similar sliding channel member and to the lower ends of the webs 21
and 22 respectively.
From the foregoing description it will be clear that as the truss
is erected from the condition of FIG. 1 to the condition of FIG.
1C, the strap member 15 is bent. It should also be noted that the
inner ends of the truss pieces 14 and 14a may be mitered as shown
respectively at 14b and 14c, so that the miter defines the limit to
which the truss may be erected and defines the desired roof pitch.
Another method of connecting truss pieces 14 and 14a, which does
not necessitate mitering of the ends of the truss pieces, will be
described hereinafter. As the truss is erected and as can be seen
very clearly in the progression of FIGS. 1A, 1B, and 1C, the bottom
of the V structure of the web 19, 21 and 20, 22 slides along the
chord 13 and similarly the sliding members 23 at the upper ends of
the webs 19 and 20 slide along the chord pieces 14 and 14a.
As described above the extension members 16, 17 and 16a, 17a are
pivotably secured together by means of the bolts 25 and it will be
understood that by extending the telescoping members 16, 17, 16a,
17a the height of the truss and the span of the truss are increased
without disturbing the desired roof pitch. Thus, a truss according
to this invention may be manufactured to serve for a variety of
spans and in fact such a truss can be made to cover all of the
commonly used spans which are found in residential and small
commercial buildings.
Once the truss has been erected to the required span the various
sliding elements are simply fixed in position by means of sheet
metal screws or other suitable fastening. A typical fastening
arrangement using sheet metal screws is shown at 26 in FIGS. 4 and
5. Similarly, of course, the extensions 16, 17, 16a and 17a will
also be secured with sheet metal screws or the like and the sliding
members at the bottom of the V configurated webs will be similarly
fixed.
The ridge portion of the truss may be fixed and secured in several
ways, two of which are shown in the drawings. In FIG. 6 there is
shown a channel member 27 having its web centrally slotted at 28
and relieved at 29. It is also provided with the predrilled holes
30. The element of FIG. 6 is shown in position in the collapsed
truss in FIG. 7A. When the truss is erected the insert member 27
bends along the line 31 and the adjacent portions of the web of the
member 27 overlap each other as clearly seen in FIG. 7B. The two
lower holes 30 coincide when the predetermined angular relation is
established and a bolt 32 secures the upper chord pieces 14 and 14a
in position. The remaining holes 30 serve to fasten the upper ends
of the web members 21 and 22, respectively. It should be noted that
in this embodiment the inner ends of the upper chord members 14 and
14a are separated, and are connected by means of the insert 27, so
that mitering is unnecessary.
An alternative construction is shown in FIGS. 8A and 8B. Here a
small plate 33 is provided which is bolted to one of the chord
pieces, in this instance the piece 14 at 34. Thus, when the truss
is erected the parts go from the position shown in FIG. 8A to the
position shown in 8B and a bolt is then inserted through the holes
35 and 36 which will now be aligned. It should be noted that the
inner ends of the chord members 14 and 14a are mitered, as shown
respectively at 14b and 14c, so that the miter defines the limit to
which the truss may be erected, and defines the desired roof
pitch.
A still further embodiment is illustrated in FIGS. 17 and 18,
wherein a one-piece upper chord is disclosed. The one-piece upper
chord 81 has its web, lower flange and upper and lower lips cut
out, as indicated at 82 and 83, leaving its upper flange only along
the line 84. The angles of the cuts 82 may be such as to determine
the roof pitch, or they may be greater, and a connector piece may
be relied upon to determine the pitch. A connector such as that
shown in FIGS. 8A and 8B may be used, either to determine the pitch
and fix the truss parts in position, or simply to fix the truss
parts in position.
Coming now to a description of a half truss and particularly a half
truss suitable for use in a panelized construction, reference is
made to FIGS. 9 to 11 inclusive. Again, the half truss 50 is shown
in a collapsed condition in FIG. 9. It consists of a bottom chord
51 and a top chord 52. It should be noted that in FIGS. 9 to 11, no
extension members are shown for the chord pieces 51 and 52 but it
will be clear that they may be added in the same manner as
disclosed in connection with FIGS. 2 and 3. The web members are
shown at 53 and 54. Again the web member 54 is pivotably bolted to
the end of the upper chord 52 at 55 and the lower ends of the webs
53 and 54 are pivotably secured to each other and to a sliding
member at 56. The upper end of the web member 53 is secured to a
sliding member 57 in the same manner as was described in connection
with FIG. 5. A web stop is provided at the inner end of the lower
chord 51 at 58. Since the channels constituting the chords 51 and
52 open toward each other in order to provide the tracks in which
the sliding pieces 56 and 57 travel, an insert 59 is secured within
the channel 51 and a plate 60 is secured to the channel 52 so that
the channels 51 and 52 may be pivotably connected to each other.
The parts are connected together by a bolt 61. In this way a neat
boxlike structure is provided for the collapsed half truss.
When the half truss is collapsed, the sliding member 57 slides
toward the left in the upper chord 52 and the sliding connection at
the bottom of the webs 53 and 54 slide toward the left in the chord
51.
In a panelized construction roof decking or sheathing is applied to
a plurality of such half trusses and thus a half roof may be
shipped direct to the site in collapsed condition. When such a half
roof arrives at the site, the plurality of half trusses having the
roof decking attached thereto are erected to the position of FIG.
10 with the sliding connection at the lower ends of the webs 53 and
54 abutting against the web stop 58. The parts are then fixed in
position as described in connection with the full truss and a half
roof including truss and decking is provided.
The building industry is now coming to a modular construction
wherein substantially a half building is prefabricated including a
side wall, two ends walls, half roof trusses, and roof decking, and
with duct work, plumbing, and electrical work already installed.
For such a purpose, the structure of FIGS. 9 to 11 is slightly
modified. Again, the collapsed half truss for modular use is shown
in FIG. 12 at 70. FIG. 13 shows the half truss in a partially
erected condition for a purpose to be described later, and FIG. 14
shows the half truss in its fully erected condition. In this
instance, the upper chord consists of a main portion 71 and a
telescoping extension 72 at its upper end. The lower chord consists
of a main portion 73 and a telescoping extension 74 at its outer
end. It should be noted that these telescoping extensions 72 and 74
are at opposite ends of the respective chord members.
The web members 76 and 75 may be in all respects just like those
indicated at 53 and 54 respectively in connection with FIGS. 9 to
11. Again, an end stop is provided at 77 and an intermediate stop
is provided at 78 in the lower chord.
With the half truss in the condition of FIG. 14, all of the
assembly work at the factory is done. The side wall and end walls
of the building are attached and the various elements of duct work,
electrical, and plumbing work are installed.
Difficulty is encountered when such a module is to be shipped from
the factory where it is assembled, to the building site. This
invention makes it possible to partially collapse the assembled
half roof truss and to make it narrower and lower for shipment
purposes. Thus, when the extensions 72 and 74 are telescoped
respectively into the members 71 and 73 and the web members 75 and
76 are caused to move to the left as described above, the half
truss may assume the position shown in FIG. 13 where the connection
between the web member 75 and 76 to the sliding member 79 abuts
against the intermediate stop 78 to hold the partially collapsed
half truss in the condition of FIG. 13. In this condition, it may
be seen that the half truss is substantially narrower and lower
than in its erected condition and is in fact no longer than it was
in its fully collapsed condition of FIG. 12. The state of the half
truss in FIG. 13 does not interfere with duct work and piping and
the like installed under the roof and yet the half truss is now of
small enough size that it can be handled with presently available
trucks without violating laws in regard to width and height of
loads traveling over highways.
Again, as shown in FIG. 15, the members 71 and 73 are disposed with
their openings facing each other and for this reason the member 71
is provided with a plate 71a having the dimple 71b so that the
connection between the upper chord 71 and the lower chord extension
74 can be made by means of bolting through the opening 80. The
connection between the upper chord extension 72 and the web 75 is
shown in FIG. 16.
It will be seen that the construction of FIGS. 9 to 11, which has
been described for a panelized construction and the construction of
FIGS. 12 to 16 which has been described as for a modular
construction, are in reality very similar, and there will
undoubtedly be instances where either construction may be used. An
additional advantage of both constructions is that they may be
erected from the right hand end as seen in these Figures, thus
permitting workmen to effect erection from outside the
construction. In connection with a modular construction, this is of
great importance.
It will be understood that numerous modifications may be made in
details of the construction without departing from the spirit of
the invention. No limitation not specifically set forth in the
claims is intended and none should be implied.
* * * * *